Implantable medical devices (IMDs) such as cardiac pacemakers, cardioverter/defibrillators, leads, and sensors are typically placed in a sterilized package by the manufacturer prior to being removed and implanted within the body. An example of a sterilized package is a blister pack, which typically includes an inner tray or pouch and a cover that seals the IMD within an interior form or chamber. The IMD is often sterilized while in the inner tray or pouch using steam, gas, ultraviolet light, or other suitable sterilization technique. A sterilization barrier such as a peelable or tearable seal can be opened to break the barrier, allowing the IMD to be removed and subsequently implanted into the patient. In some cases, other components may also be removed from the sterilized packaging for use in preparing the IMD for implantation.
For some types of IMDs, it may be desirable to test the operation and functionality of the IMD prior to breaking the sterilization barrier, while the IMD is still within the packaging. For an implantable sensor configured for insertion within the body, for example, it may be desirable to test the operation of the sensor prior to breaking the sterilization barrier and removing the sensor from the packaging. In the case of a pressure sensor, for example, it may be desirable to verify the accuracy and functionality of the pressure sensor while still in its packaging. In some cases, it may also be desirable to program the sensor, to verify the correct programming of the sensor, and/or to recharge a battery or to verify the battery capacity within the sensor prior to removal from the packaging.
In some cases, communication with IMDs located within the sterilized packaging can be difficult due to the complex communication pathway between the IMD and the device interrogating the IMD. For an IMD adapted to acoustically communicate with another device such as an external interrogator, for example, the presence of air or other gases in the acoustic pathway between the interrogator and the sensor can inhibit communication.